Personal cloud storage services enable end users to access data using any device at any location. There are many ways for an end user to transfer files to a personal cloud storage of the end user, the most common being for the end user to transfer files from devices of the end user to personal cloud storage servers operated by the personal cloud storage service provider that is providing the personal cloud storage service. While this approach may be sufficient for existing files that are stored on the devices of the end user, this approach is inefficient for files not stored on the device of the end user (e.g., files stored on servers of other service providers, files located on other end user devices, and the like).